Re: glyph item split
On 05/27/11 12:55, august wrote: The split_index is said to be: byte index of position to split item, relative to the start of the item Can you explain what this means in more detail? What is the start of the item? How do I get that? The item corresponds to a chunk of the text, say, from start to end. start is what you want. It's recorded in item-offset actually. So this should work, if everything else is correct: Pango.GlyphItem vorn = glyphitem.split ( text, glyphitem.glyphs.log_clusters[gi.end_index] - glyphitem.item.offset) thanks for the reply. Can you tell me what happens to the glyphitem and the gi when I make that split? The following code goes through a text line by line, run by run, and glyphitem by glyphitem. It then tries to split off the first cluster and continue in the loop. http://pastebin.com/Ewi3c1UD Line 79 is where the split happens. I'm sure this changes the glyphitemiter somehow, but don't know how to do it so that I can continue inside that loop. Any suggestions? You may want to check the source code in situations like this. I couldn't find anything that is doing something similar to what I want. any help would be appreciated. many thanks -august. ___ gtk-i18n-list mailing list gtk-i18n-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-i18n-list
Re: Drawing glyph bounding box on rendered text?
Behdad posted a python application that draws lines around clusters,
runs, and lines:
http://mail.gnome.org/archives/gtk-i18n-list/2011-April/msg7.html
Maybe you haven't seen that yet and can help.
best -august.
Hi all,
I'm trying to accurately draw a rectangle around each glyph (not
character) in rendered text. I'm very close but things aren't quite
lining up correctly. I've attached an image showing this, but if the
mailing list filters it, you can also see it here:
http://www.phonething.com/test.png
Green box shows line extents, red boxes should show bounding box for
each glyph.
As you can see, widths and X starting positions of the boxes are off
slightly. (So is height, but I suppose I could lock that to the
bottom of the line extents?)
Relevant code that drew that is:
double pango_to_ink = (1.0 / ((double) PANGO_SCALE)); // utility
[ create surface, context, layout, then do pango_layout_set_text() ]
[ for each line in layout use pango_layout_iter_get_line() : ]
pango_layout_iter_get_line_extents(pIter, line_r, NULL);
pangolineX = pango_to_ink * ((double) line_r.x); // start position
of this line of the layout
pangolineY = pango_to_ink * ((double) line_r.y);
[ get each run in current line: ]
for (i = 0; i pRun-glyphs-num_glyphs; i++) // loop through
glyphs in current run
{
pango_font_get_glyph_extents(font, glyphID, NULL, glyphbox);
// Just to get glyph height as it's not in the geometry
glyphX = pangolineX + pango_to_ink * ((double)
pRun-glyphs-glyphs[i].geometry.x_offset);
glyphY = pangolineY + pango_to_ink * ((double)
pRun-glyphs-glyphs[i].geometry.y_offset);
glyphW = pango_to_ink * ((double)
pRun-glyphs-glyphs[i].geometry.width);
glyphH = pango_to_ink * ((double) glyphbox.height);
cairo_rectangle(context, glyphX, glyphY, glyphW, glyphH - glyphY);
cairo_stroke(context);
}
Where am I going wrong in getting the glyph bounding boxes
accurately? (this needs to also work for Indic, Hebrew, Arabic,
Chinese and so on)
It doesn't matter if the box has empty space, i.e. incorporates the
distance between glyphs, though knowing the actual glyph bounding
box AND the space separating it from the next glyph
would be ideal.
Thanks and regards,
Alex
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Re: Drawing glyph bounding box on rendered text?
Whoops sorry. Fired that off without noticing he sent that code to you originally. I go back into lurker mode. Appologies. Behdad posted a python application that draws lines around clusters, runs, and lines: http://mail.gnome.org/archives/gtk-i18n-list/2011-April/msg7.html Maybe you haven't seen that yet and can help. best -august. ___ gtk-i18n-list mailing list gtk-i18n-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-i18n-list
Re: pango_cairo_show_glyph_item_range ?
On 11/01/10 20:22, august wrote: Would it be possible to have a pango_cairo_show_glyph_item_range function that would take a start and end value? This would be very useful. I agree. Filed a bug: https://bugzilla.gnome.org/show_bug.cgi?id=633926 Feel free to submit a patch. Or I'll get to it next time I'm adding Pango API. behdad Have you started on this already? If not, I will look into it now. IF you can, please advise me on where to start. -august. ___ gtk-i18n-list mailing list gtk-i18n-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-i18n-list
Re: go from PangoGlyphItemIter to an index into a PangoLogAttr ?
My main problem, which I have partially solved, is how to iterate through a layout (line by line, run by run, and then glyphitem by gitem) and keep the log_attributes I get from the layout in sync with my iteration. I noticed that when I change the set_width() of my layout, the number of characters in the layout/log_attr array changes. Why is that? I was surprised when I found this out...but still don't know how it changes the character count. Is there now an extra char in my log_attr for every line or run or some mixture? I ran some tests where I increment my index into the log_attr array for each line or run, but did not see any regularity. My solution for now is to not set_width on the layout. I've also tried to get an index into the log_attr array using log_attr[glyphitemiter.glyph_item.glyphs.log_clusters[i]] where i is incremented for every call to next_cluster() however, this does not work ( at least not when you set_width on the layout). I think I can narrow my question down a bit. I the pango docs for pango_layout_get_log_attr() it says: n_attrs: location to store the number of the attributes in the array. (The stored value will be one more than the total number of characters in the layout, since there need to be attributes corresponding to both the position before the first character and the position after the last character.) So, when I do this, I know the number of characters in the layout. I can also count the number of characters in the source text fed into the layout. However, what I don't know is the correlation between the # characters in the layout and the # characters in the source text. They are not the same. -august. ___ gtk-i18n-list mailing list gtk-i18n-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-i18n-list
go from PangoGlyphItemIter to an index into a PangoLogAttr ?
Hi, Could someone tell me how to go from a PangoGlyphItemIter to and index into a PangoLogAttr that comes from pango_layout_get_log_attrs? My code first gets a layout and sets the text. Then, I do get_log_attrs on the text. The pango docs say that the get_log_attrs function Retrieves an array of logical attributes for each character in the layout. What does character mean in that sentence? Then, after getting the log_attrs, I get a layout iter and step through the text by line, run, and then by glyphitemiter.next_cluster. Is there no direct way to index back into my log_attrs[] array from the glyphitemiter? thanks for any tips. I've been staring at this for so long now. best -august. ___ gtk-i18n-list mailing list gtk-i18n-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-i18n-list
some questions about runs, glyphs, chars, bytes, clusters
Hi,
I am making some tests to try and learn more about Pango. Right now
I am trying to step through a layout line by line, run by run, and
then word by word.
I was hoping someone might be able to help me out with some
questions.
Here is what I am doing.
static char * text = { flower power };
// I get the layout
PangoLayout *layout;
layout = pango_layout_new(pango_context);
pango_layout_set_text(layout, text, -1);
pango_layout_context_changed(layout);
// I then get iterators for lines and stuff
PangoLayoutIter* p_iter = 0;
p_iter = pango_layout_get_iter(layout);
PangoLayoutLine* p_line = pango_layout_iter_get_line(p_iter);
GSList* current_run = p_line-runs;
PangoLayoutRun* p_run=(PangoLayoutRun*)current_run-data;
// I then try to get attribute info for this run
PangoLogAttr * logattrs = (PangoLogAttr *) malloc(
(p_run-item-num_chars +1 ) * sizeof(PangoLogAttr) );
pango_break(text+ p_run-item-offset, p_run-item-length,
p_run-item-analysis, logattrs,
p_run-item-num_chars+1);
// Am I doing this wrong?
// This then gives me a PangoLogAttr for every byte char in the text
// string, correct? But, since there could be more than one char for
// a glyph, where do I check for word_end?
// Can someone tell me here what num_chars refers to in the item?
// is that character bytes?
// is that not always the same as item-length?
// Also, what is the difference between a byte, a character, a glyph,
// and a cluster in Pango? In the docs and naming of variables, is
// it consistently named?
// Then, I try to step through the run by glyph and logattr to see
// where words start and end
// Is this correct?
for(int i=0;ip_run-glyphs-num_glyphs;i++) {
j=p_run-glyphs-log_clusters[i];
// I print out some info about the word start and end
printf(\t\tword_start:%d, , logattrs[j].is_word_start);
printf(word_end:%d \n, logattrs[j].is_word_end);
}
The funny thing that I notice heres is that the f and the l in
flower is considered one glyph. Is that right?
Sorry if my questions are basic. I can see how complex type layout
is now that I am getting my hands dirty. Any help would be greatly
appreciated.
thank you -august.
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glyphs
Hi,
I'm a newbie to pango low-level functions and am trying to learn how
to use pango_itemize, pango_break, and pango_shape properly.
Given an item from pango_itemize, I do:
PangoGlyphString *glyphs = pango_glyph_string_new();
pango_glyph_string_set_size(glyphs, item-num_chars);
pango_shape(text+item-offset, item-length, item-analysis, glyphs);
printf(number of glyphs: %d \n, glyphs-num_glyphs);
for (int j=1;j glyphs-num_glyphs ;j++){
// crashes here
printf(#%d, guint32 glyph=%d\n, j, glyphs[j].glyphs-glyph );
}
What am I doing wrong?
thanks -august.
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Re: glyphs
Hi,
I'm a newbie to pango low-level functions and am trying to learn how
to use pango_itemize, pango_break, and pango_shape properly.
Given an item from pango_itemize, I do:
PangoGlyphString *glyphs = pango_glyph_string_new();
pango_glyph_string_set_size(glyphs, item-num_chars);
pango_shape(text+item-offset, item-length, item-analysis, glyphs);
printf(number of glyphs: %d \n, glyphs-num_glyphs);
for (int j=1;j glyphs-num_glyphs ;j++){
// crashes here
printf(#%d, guint32 glyph=%d\n, j, glyphs[j].glyphs-glyph );
}
What am I doing wrong?
it figures that I have been staring at this for a few hours already and
notice my mistake right after I send for help to the list.
It should be:
printf(#%d, guint32 glyph=%d\n, j, glyphs-glyphs[j].glyph );
sorry for the noise.
But, if anyone has a link to some readable example code using
pango_itemize, pango_break, and pango_shape, I'd really appreciate it.
I cannot find anything online.
-august.
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iterate through a layout by char or word?
Is there any way to iterate through a PangoyLayout by character or word? Is there a way to iterate by word and then show it using cairo? I can do something similar with pango_itemize, pango_break, and pango_shape. But, I can't seem to do anything with the resulting PangoGlyphString that I get. I can do pango_cairo_show_glyph_string(), but I want to just show a word or character. Is there something like pango_cairo_show_glyph_string_range()? I can do pango_glyph_string_copy(), but cant do anything like strncpy where I can just get a segment of that PangoGlyphString. Any tips would be greatly appreciated. thanks -august. ___ gtk-i18n-list mailing list gtk-i18n-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-i18n-list
memory leaks on pango examples
hi, I'm trying to debug some of my code (which is based on the example code provided by pango), and came across a bunch of memory leaks. I'm still new to valgrind, so can anyone explain to me why there are leaks with: valgrind --leak-check=full ./cairosimple blah.png where ./cairosimple is the example program provided in the pango source dir. thanks -august. ___ gtk-i18n-list mailing list gtk-i18n-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-i18n-list
Re: pango layout in irregular (non-rectangular) bounding shape
august, I can already render stuff to screen and bound a text segment by width and height I guess you tried PangoLayout and friends. how to render text within a non-rectangular bounding shape? Can someone point me in the right direction? If I were you, I'd be using PangoItem, PangoGlyphString, and friends. They are lower layer interface to pango, and you need to write more codes than using PangoLayout, but it gives you better control over layout. (There may be some easier ways if you only needs fill texts ina non rectangular area, but I don't know.) The following outlines what you need to do: (1) Call pango_itemize() once for your text, (2) Call pango_break() for your entire text, (3) Call pango_shape() for each PangoItem you got, (4) Fold the text into lines, scanning the list of PangoItems, calling pango_glyph_string_get_width() for each PangoGlyphString you got, also breaking several PangoItem in a middle, referring to PangoLogAttr array you got (This will be the most complicated step), (5) Either call pango_reorder_items() for each folded line and somehow refrect the results to your list of PangoGlyphString (or does an equivalent processing manually as suggested by pango document...), and (6) Call pango_cairo_show_glyph_string() for each PangoGlyphString, moving the cairo current point appropriately. Hope this helps, Alissa Alissa, thanks so much for taking the time to outline all of this. I am still learning the pango api and this helps. -august. ___ gtk-i18n-list mailing list gtk-i18n-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-i18n-list
Re: pango layout in irregular (non-rectangular) bounding shape
In addition, I'd like to render text inside a polygon shape. This is not possible yet. Here is the bug tracking this issue: http://bugzilla.gnome.org/show_bug.cgi?id=435706 Behdad, How far did you get with that? I also see you were looking at Nathan Hurst's code for inkscape. I'd love to study some of that code...but it seems like most of the links on that page are gone now. Is this something I could help implement? -august. ___ gtk-i18n-list mailing list gtk-i18n-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-i18n-list
GLib new user + Quarks and Hash Tables
I am currently working on a research compiler and simulator for computer
architecture (i.e. design your own novel hardware feature, compile for it,
simulate, measure benefit). I have very recently become interested in GLib
and have thought of replacing parts my current home-grown library with it if
it makes sense to do so. My first task was the replacement of our symbol
table.
The hash table/symbol table I currently use maps a string (or any type) to a
pointer (string-pointer) just like GLib's hash table. However, there are
forms of the add and find functions which return a unique identifier (the
symbol) much like your quarks. This unique identifier is used in other
higher level structures to quickly return either the string or the pointer.
It is also used for equality/inequality comparisons with other symbols.
This unique identifier (or symbol) is currently implemented as a pointer to
the hash table element, but this is hidden from the user with functions
implemented very simply as: (pseudo code here)
get_pointer_from_symbol(symbol) {symbol-pointer}
and
get_string_from_symbol(symbol) {symbol-string}
Alternatively, the unique identifier could be an int (or quark) and these
function could return the results of an array lookup, etc.
As I tried to port my compiler's symbol table to GLib I ran into a small
concern. Basically, I need to use quark to map a string to a unique int
(which I can use as a symbol and compare in the higher level structures) and
a hash table to map the unique int to the pointer.
The inefficiency with this in GLib is that it utilizes two hash tables. In
addition to space concerns, two lookups are necessary to go from a string to
pointer. My question is:
Is there a better way to do this in GLib?
If not:
Can we augment the hash table to return a unique symbol (polymorphic
quark-like item) for some versions of add, find etc?
These unique symbols are essentially polymorphic quarks which might be a
nice thing to offer anyway. This change would also make the implementation
of string quarks simpler, faster, and more space efficient. (Quarks would
basically be a hash table of strings-NULL. The quark would be the
symbol/pointer to the hash table element. The string would be accessible by
symbol by a single dereference. The pointer to NULL would basically be
ignored. No array necessary.)
Thank you in advance for your help.
David
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